Systems and methods for performing endometrial ablation

ABSTRACT

A method and system of providing therapy to a patient&#39;s uterus is provided, which can include any number of features. The method can include the steps of inserting a uterine device into the uterus and performing a uterine integrity test to determine that the uterus is intact and not perforated. If it is determined that the uterus is not perforated, a patency test can be performed to determine that the uterine device is not clogged or embedded in tissue. If the uterus is intact and the device is not clogged or embedded in tissue, the uterus can be treated with the uterine device, e.g., uterine ablation. Systems for performing these methods are also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/006,265, filed Jun. 12, 2018, now U.S. Pat. No. 10,299,856; whichapplication is a continuation of U.S. application Ser. No. 14/719,048,filed May 21, 2015, now U.S. Pat. No. 9,993,290; which applicationclaims the benefit of U.S. Provisional Application No. 62/002,082, filedMay 22, 2014, titled “Systems and Methods for Performing EndometrialAblation”, all of which are incorporated herein by reference.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

FIELD

The present disclosure generally relates to uterine proceduresincorporating a distension media such as a fluid or a gas that could beused with endoscopic procedures or other visualization systems suchultrasound or fluoroscopy. The present disclosure is particular suitedfor endometrial ablation of the uterine lining. More specifically, thepresent disclosure relates to endometrial ablation with a heated vapor.

BACKGROUND

Endometrial ablation (i.e., the removal or destruction of theendometrial lining of the uterus) is used as an alternative tohysterectomy for treating menorrhagia, or other uterine diseases. Oneprior technique for performing endometrial ablation employs aresectoscope (i.e., a hysteroscope with a built-in wire loop or otherablative devices) that is inserted transcervically into the uterus, anduses radio-frequency electrical current (RF current) to remove orcoagulate the endometrial tissue. These standard techniques typicallyare performed in a hospital setting and importantly utilize hysteroscopyfor visualization of the procedure while treating the uterine lining.

Some approaches make use of heated fluid to ablate the endometrium. Forexample, early journal articles describe the use of steam to treatuterine hemorrhage. The use of steam for this purpose was laterdiscredited, apparently due to patient morbidity and mortality. See,e.g., Fuller U.S. Pat. No. 6,139,571. More recent descriptions of theuse of injecting hot fluid into the uterus have been described. Uterinetherapies employing a contained fluid have also been described.

In an effort to simplify the procedure, approaches have been developedthat do not require concurrent hysteroscopic visualization. In practice,many of these techniques recommend that the physician or user employhysteroscopy to visualize and inspect the uterine cavity prior toperforming the endometrial ablation procedure. In addition, hysteroscopymay be employed at the conclusion of the endometrial ablation procedureas a method to inspect the uterine cavity post treatment. During thishysteroscopic inspection, the physician is verifying that the uterinecavity is not perforated although perforations may not be readilyapparent even with hysteroscopic visualization. In general, a physicianseeks to avoid perforations for many reasons including the potential forunintended injuries to neighboring organs and maintaining or confiningthe treatment area to specifically the uterine cavity in the case ofendometrial ablation procedures.

Endometrial ablation techniques that do not require active hysteroscopicvisualization during treatment operation are commonly referred to as“blind” techniques since the physician is using tactile feel, or markersand indicia on the endometrial ablation device to indicate properplacement of the device in the uterine cavity. One of these particulardevices utilizes a balloon-based system using heated saline as thethermal energy source for the ablation of tissue. High frequency, orradiofrequency (RF), energy has also been used to perform thermalablation of endometrial tissue. Current products for performingendometrial ablation include the NOVASURE® procedure and a systemmarketed under the trade name THERMACHOICE®, by Ethicon, Inc. ofSomerville, N.J. Cryogenic ablation, or “cryoablation,” such as HEROPTION® from American Medical Systems, Inc., is another endometrialtreatment approach. All of the products above are characterized as“blind” or not requiring direct hysteroscopic visualization during thetreatment.

In utilizing an endometrial ablation technology that does not requirehysteroscopic visualization, it would be beneficial to employ a test toverify that the uterine cavity is intact or unperforated prior toperforming the treatment. Such tests are referred to as uterineintegrity tests and these tests can be performed with endometrialablation procedures and any procedure of the uterus or hollow bodycavity or organ. In addition, these tests can be used with hysteroscopicprocedures since a perforation may not be readily detected even underdirect vision.

Integrity tests employ saline or gas, preferably carbon dioxide gas, asagents to verify if the uterine cavity is intact in regards to holdingfluid or gas pressure. The gas or fluid is supplied under pressure tothe uterine cavity and a leak in the uterine cavity, whether it is aperforation, an unsealed cervical canal, or the effect of excess fluidexiting the fallopian tubes, can be discerned. Stern et al. (U.S. Pat.No. 5,562,720) and Sampson et al. (U.S. Pat. Nos. 6,554,780, 6,743,184,6,872,183, and 7,063,670) describe such pressure techniques while otherapproaches check for fluid imbalances between an input source and outputcollection using volume measurements. Other approaches mention usingflow rate and pressure measurements.

For monitoring the therapeutic energy application during the procedure,some technologies monitor the internal pressure of heated saline withina balloon that is placed within the uterus, or the impedance of radiofrequency energy within the wall of the uterus. These technologies haveautomatic termination steps if the pressure, impedance, or volume levelsreach certain thresholds. At the initiation of the procedures for all ofthe above mentioned systems, the inaccurate placement and management ofthe therapeutic device by the physician within the uterine cavity canreduce the ability to perform a safe and consistent ablation procedure.For these technologies, the ability of the device to perform a completeendometrial ablation procedure depends upon the tactile movements andplacement of the device by the physician in terms of depth of placementor achieving complete contact with the interior lining with the deliverydevice mechanism. As an example, a radio frequency device deploys an RFarray within the uterine cavity. The depth of insertion can vary bypatient and physician. By not contacting the endometrium in more distalor proximal locations, the efficacy of the procedure could alter or beaffected. For thermal balloon procedures, a similar effect can occur dueto the depth of device placement. For both of the technologies, thesystem cannot provide information or assessment for the proper andconsistent placement of the device in the uterine cavity. Alternatively,an amorphous ablation technology such as the free flow of heated salinedoes not have this physical limitation however even this technology,known as Hydro Thermo Ablation or HTA, relies heavily on the placementof the device by the physician to prevent leaking out of theendocervical canal.

Systems that depend heavily on physician manipulation or interventionduring the procedure have been characterized as being “techniquesensitive”. The requirement for a physician to properly manipulate adelivery device and react appropriately before and during an endometrialablation procedure can lead to an increase of adverse events orunreliable patient outcomes. This is particularly evident when thresholdvalues prior to and during a procedure fall within a range requiringphysician intervention or adjustment.

The following describe a control system that overcomes thesedeficiencies for a technology that provides vapor energy in combinationwith a number of unique and sequenced steps designed to ensure patientsafety and procedural consistency. The control system also assessesdelivery device placement and sealing within the uterine cavity andendocervical canal by providing information for the physician whenadditional pressure within a sealing balloon at the cervix may beneeded.

SUMMARY

An endometrial vapor ablation system, comprising a vapor generator, auterine ablation device coupled to the vapor generator, the uterineablation device configured for insertion into a uterine cavity of apatient, a control system coupled to the uterine ablation device and thevapor generator, the control system being configured to automaticallyperform a pre-procedural sterilization of the vapor generator and theuterine ablation device, the control system configured to prep theuterine ablation device for vapor delivery, the control systemconfigured to test safety components of the uterine ablation deviceprior to and after insertion into the patient, the control systemconfigured to monitor the application of vapor energy, monitortemperature reading at identified locations on the uterine ablationdevice, and the control system being configured to implement shutdown ofthe vapor generator following vapor delivery.

In some embodiments, the electronic controller is configured to promptan end user of the uterine ablation device if the pre-proceduralsterilization fails to initiate or complete.

In another embodiment, the electronic controller is configured to promptan end user of the uterine ablation device if the testing of the safetycomponents indicates an error in the system.

In some embodiments, the system further comprises a distal anchorballoon, a central sealing balloon, and a proximal positioning balloondisposed on a shaft of the uterine ablation device.

In one embodiment, the system further comprises a temperature sensorpositioned near the central sealing balloon and configured to measure atemperature inside an endocervix of the patient.

In yet another embodiment, the system further comprises one or morepressure sensors configured to measure a pressure of each of the distalanchor balloon, the central sealing balloon, and the proximalpositioning balloon.

A method of providing vapor therapy to a uterus of a patient isprovided, comprising the steps of sensing a fluid level of a vaporgenerator, heating the vapor generator to prepare a condensable vapor,priming the condensable vapor through a uterine ablation device coupledto the vapor generator to sterilize the uterine ablation device,comparing a pressure sensor value within the uterine ablation device toa pressure sensor value within the vapor generator, verifying theintegrity of a plurality of positioning and sealing balloons of theuterine ablation device, delivering condensable vapor from the uterineablation device into the uterus, and during the delivering step,monitoring a temperature in a cervix of the patient and automaticallyterminating delivery of condensable vapor if the temperature exceeds athreshold value.

In some embodiments, the threshold value comprises 44 degrees C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D illustrate one embodiment of a uterine ablation device.

FIG. 2 shows an embodiment of a uterine ablation device inserted into auterus.

FIG. 3 illustrates an integrity test of the uterine ablation device.

FIG. 4 illustrates a patency test of the uterine ablation device.

FIG. 5 charts the relationship between outflow valve pressure, uterinecavity pressure, and flow through a uterine ablation device.

DETAILED DESCRIPTION

FIG. 1A illustrates a uterine ablation device 100 sized and configuredto access the endometrium of a uterus and to deliver a heated vapor tothe uterus to ablate uterine tissue. The device can be configured toablate and treat the endometrial lining of the uterus as an alternativeto hysterectomy for treating menorrhagia or other uterine diseases. Insome embodiments, the device 100 can be configured to gain access to theuterus by being inserted through a cannula or hysteroscope. The device100 can include shaft 102, handle 104, distal tip 106, vapor ports 107,distal anchor or distal balloon 108, central or sealing balloon 110,proximal or positioning balloon 112, and connection lumens 118, whichcan couple the uterine ablation device to a control system (not shown)comprising a computer, a vapor generation system, and mechanismsconfigured to inflate and deflate the balloons as well as control thedelivery and removal of integrity gas/fluid and vapor from the device.Additionally, connection lumens 118 can connect device 100 to a vaporgenerator or vapor source 121, gas/fluid source 122, pressure regulator124, and flow meter(s) 126. In some embodiments, the vapor generator 121can include an integrated electronic controller configured to controlall aspects of the uterine ablation device, including vapor generationand delivery. In other embodiments, the controller is located in othercomponents of the device, or comprises a separate control unit, such asa computer, smartphone, or tablet that is electronically coupled to thedevice. Vapor ports 107 near the distal tip 106 of the device can befluidly coupled to the connection lumens 118 via inflow and outflowlumens (not shown). The vapor ports, inflow and outflow lumens,connection lumens, gas/fluid source, pressure regulator, and flow meterscan be configured for testing the integrity of the patient's uterus,proper placement of the device, and verifying the presence of flowbetween the inflow and outflow lumens of the device. Thermocouplesand/or temperature sensors can be disposed in various places within oroutside the uterine ablation device, including within or near the inflowand outflow lumens of the device. The thermocouples can be configured tomeasure temperature information relating the flow of fluid and/or gas inthe device, as well as the temperature within patient body cavities.

The flow meter can be any flow meter as known in the art, including athermal mass flow meter, an ultrasonic flow meter, a paddlewheel, or avariable area flow meter. In one embodiment, an ultrasonic flow meterthat utilizes transit time and Doppler flow readings is advantageoussince it is a non-contact system that does not need to physicallyinteract with the fluid or gas media being employed in the integritytest. An ultrasonic flow meter can be easily adaptable to the exteriordimensions of an inflow lumen. In addition, a drip chamber within theinflow lumen can be used to manually visualize or record drips or flowfrom the fluid source as the integrity test indicates a sealed uterinecavity. In some uterine procedures, it may be advantageous to use othertypes of fluid besides saline including Lactated Ringers, non-isotonicsolutions for certain electrosurgical procedures, gels, foams, fluids ofvarying viscosity for some ultrasonographic procedures, or other fluidsused in uterine procedures.

In one embodiment, a one way valve can be placed in the inflow lumen oneither side of the flow meter relative to the gas/fluid source. The oneway valve can allow for the flow of gas/fluid (e.g., saline) from thegas/fluid source to the device and uterine cavity. The one way valveshould not interfere with the operation of the flow meter and itsreadings. In operation, the uterine cavity is a muscle that can undergosignificant contractions during the integrity and patency tests. Thesecontractions can push the fluid retrograde back through the saline lumenand past the flow meter. In doing so, flow meter measurements can becomedifficult to interpret or may produce sinusoidal waves in the outputreadings. The placement of the one way valve in the inflow lumen caneliminate retrograde fluid flow and stabilize readings for the flowmeter during episodes of uterine contractions.

Handle 104 can be an ergonomic handle and can include features andcontrols for using the device (e.g., buttons, levers, indicia forproviding feedback for depths of insertion, valves, etc.), includingfeatures for controlling inflation of balloons 108, 110, and 112, andfor controlling the delivery and removal of integrity test gas/fluid andheated vapor from the device. The handle can also include features andcontrols for testing the integrity of the patient's uterus, properplacement of the device and verifying the presence of flow between theinflow and outflow lumens of the device.

The balloons described herein can be any type of flexible balloon, suchas rubber, latex, urethane, silicone, PET, LDPE, parylene, nylon, PE,combinations of these polymers, or can be manufactured from any othersuitable material as known in the art. It should be noted that in someembodiments, the distal anchor comprises a balloon, but in otherembodiments, the distal anchor comprises an expandable anchor orexpansion mechanism, such as expandable frames, filters, nets, or cages,or non-expandable components that increase the diameter of the shaft ofthe uterine ablation device. For purposes of this disclosure, however,the distal anchor may be referred to as a distal anchor or as a distalballoon.

Shaft 102 can be configured to deliver a heated vapor from a remoteboiler (not shown) through the device and out of vapor ports 107 indistal tip 106. The shaft can also be configured to return vapor thathas exited the device, including bodily fluids, uterine materials, andcondensate back through the vapor ports and into the shaft. In FIG. 1A,vapor ports 107 are illustrated as including both the vapor delivery andvapor return ports. However, in other embodiments, the vapor deliveryports can be separate and distinct from the vapor return ports. Forexample, vapor delivery ports are intended to provide an evendistribution of heated vapor through a cavity, and may comprise smalllumens or holes on the end of the shaft. The vapor return ports, incontrast, are intended to return used vapor and condensate, and maycomprise larger slots to prevent blood, tissue, etc. from blocking orclogging the return lumen. The device comprises inflow and outflow gasand/or fluid delivery channels to conduct uterine integrity and patencytests. In some embodiments, the lumens to deliver and return vapor arethe same as the channels to deliver and return gas and/or fluid for theuterine integrity and patency tests.

Referring still to FIG. 1A, uterine ablation device 100 is shown in acollapsed delivery configuration, with distal balloon 108, sealingballoon 110, and positioning balloon 112 deflated to reduce the crosssectional diameter of the device and can be 6 mm in diameter duringinsertion or smaller. When the device is in the delivery configuration,the reduced profile allows for easier access to through the vagina,cervical canal, and cervix to gain access to the uterus, and providesreduced patient discomfort during insertion. In some embodiments, theouter dimensions of the uterine ablation device are such thatintroduction of the device into the uterine cavity can be achievedwithout the need for mechanical or pharmacological dilation of the osprior to device introduction.

FIG. 1B illustrates the uterine ablation device 100 of FIG. 1A with allthree balloons inflated, including distal balloon 108, central sealingballoon 110, and positioning balloon 112. The central balloon can beinflated with a fluid, such as saline, or alternatively, can be inflatedwith air. Although three balloons are depicted in FIG. 1B, in othervariations one, two, four, or more balloons may be provided, and otherballoon shapes may be used. The positioning balloon can be inflated witha room temperature medium, a cooled medium, or alternatively, a heatedmedium. In some embodiments, the central sealing balloon comprises alength along shaft 102 of approximately 15 mm to 25 mm. The centralballoon can be disposed on the shaft between the distal balloon oranchor and the proximal balloon. In some embodiments, the centralballoon is adjacent to both the distal balloon and the proximal balloon.In other embodiments, there is a small gap or space between one or moreof the balloons. The length and position of the central balloon on theshaft ensures that when inflated, the central balloon seals the cervixoff from the uterus near the internal os, but the balloon does notextend into the uterus or into the vagina of the patient. The centraland proximal balloons can comprise any diameter, but preferably shouldhave a diameter large enough to be able to engage the walls of thecervix and/or the vagina in the average female patient. For instance,the central balloon may have an inflated outer diameter of 10 mm andaccommodate 9.5 psi of pressure in actual use. The proximal balloon canhave a larger diameter, such as 17 mm and a lower inflation pressure of7 psi.

FIG. 1C is another view of the uterine ablation device 100 includingsome additional features. Check valve 144 can connect a vapor deliveryconduit to the handle of the device, allowing vapor or other ablationmedia to be delivered from into the handle. Valve 128 c can be a balloonvalve configured to control the flow of media through an outflow lumenof the device. The outflow lumen can be used, for example, to remove gasor fluid media from the uterus to a waste container, which will bedescribed in more detail below. Tenaculum stabilizer 146 can also beseen on the device 100 and can be configured to provide a mechanism tohold a tenaculum and vapor probe handle to maintain position relative tothe cervix.

FIG. 1D is another view of the uterine ablation device 100, furtherillustrating a tip cover 148 disposed over the distal portion of theshaft of the device, including the distal, central, and sealingballoons, and the vapor ports and distal tip. The tip cover can be usedin pre-procedure pressure sensor and balloon checks prior to insertingthe device in a patient, which will be described in more detail below.

One embodiment of a pre-procedure check will now be described. In oneembodiment, the uterine ablation device is activated by the user and thenecessary accessories and device are attached to the vapor generator.Upon attachment of the device handle to the generator, the accessoriesare sensed and registered by the electronic controller of the uterineablation device. Various sensors in the device, such as a water ionsensor and fluid level sensor can provide sensed data to ensure that theproper fluid and amount of fluid have been added to vapor generator andgas/fluid source. The uterine ablation device can then prepare the vaporgenerator to perform an ablation procedure by heating the generator toits operating levels and priming steam throughout the internals of thesystem for a prescribed period of time, ranging from 1 to 5 minutes. Theinternals can include delivery and return vapor paths within the uterineablation device. The running of vapor at an appropriate temperature andpressure throughout the internal equipment for a prescribed period oftime ensures that the equipment is sterilized for use in a medicalprocedure. In one embodiment, during this sterilization process, thesystem can prevent connection of the vapor delivery conduit of thedevice to avoid disruption of the sterilization cycle.

Once sterilization is complete and the vapor delivery conduit isconnected, it can be locked into place to prevent inadvertent disruptionor disconnection during the rest of the procedure. The vapor deliveryconduit of the uterine ablation device can then be pre-heated byallowing vapor to circulate within the vapor delivery conduit. Thetemperature can then be monitored by a thermocouple in a return path ofthe generator or a return path of the uterine ablation device. Oncecompleted, the device can notify the user that the generator unit isready for the next step in the preparation process, or the device canautomatically move on to the next step in the preparation process.

While the sterilization or vapor priming process is occurring, apressure sensor of the uterine ablation device can be registered, andthe pressure reading from the sensor can be compared with a referencesensor within the generator unit. Furthermore, the controller can testthe integrity of the three balloons (e.g., distal, central, and sealing)on the device. The system will not allow the process to continue unlessall parameters tested meet specifications. In one embodiment, thedistal, central, and sealing balloons can be inflated inside the tipcover 148 to a test pressure and checked for leaks. The tip cover can besupplied on the uterine ablation device to also protect the productduring shipping and handling within the procedure room. With the tipcover on and the distal, central, and sealing balloons inflated, achamber created inside the tip cover is pressurized with air through alumen of the device to compare a pressure sensor reading of the deviceto a reference pressure sensor in the vapor generator.

The electronic controller can be configured to prompt the user if thepre-procedural sterilization of the vapor generator or the uterineablation device is not initiated or completed correctly. The controllercan also be configured to prompt the user if the distal, central, andsealing balloons have leaks, or if the pressure and/or temperaturesensors indicate a problem with the uterine ablation device or the vaporgenerator. In some embodiments, the electronic controller can preventthe delivery of condensable vapor to the patient if any of thepre-procedural checks or preparation steps indicate a problem or fail tocomplete.

Upon passing the testing of the pre-procedure checks described above,the controller and vapor generator can perform a fluid priming operationto run saline or another fluid through the uterine ablation device inpreparation for insertion into the patient. During fluid priming, properoperation of the device can be verified by checking signal strength inthe flow sensor and establishing a reference zero flow. The user canthen be notified by the system that the uterine ablation device can beinserted into the patient. The tip cover is removed from the distal endof the device prior to insertion.

Placement of the ablation device of FIGS. 1A-1D will now be described.The distal tip of the ablation device can be inserted past an externalos into the cervical canal of the patient, and past an internal os ofthe patient to gain access to the uterus. In one embodiment, the distalballoon can be positioned within the uterus distal to the internal os,the sealing balloon can be positioned at or proximal to the internal osand extending into the cervical canal, and the positioning balloon canbe positioned within the cervical canal and extending proximally into ortowards the vagina.

Once the distal tip of the ablation device is disposed within theuterus, just distal to the internal os, the distal balloon can beinflated to the desired pressure. In some embodiments, the balloon canbe inflated to a pressure of up to approximately 20 to 30 psi so as toprevent accidental withdrawal of the ablation device from the uterus. Itshould be noted that at this point, the distal balloon is positionedslightly past the internal os of the cervix. Inflation of the distalballoon can later serve as an anchor to prevent the device from slidingproximally out of the uterus. The user or physician can tug gently onthe device to confirm that the distal balloon is in the uterine cavity.

After inflating the distal balloon, the proximal balloon can be inflatedto cause the device to assume a positioned configuration, with thedistal balloon fully seated against the internal os and the positioningor proximal balloon expanded within the cervix and extending past theexternal os into the vagina. As the proximal balloon is inflated, theballoon can expand outwardly from the cervix into the relativelyunconstrained space of the vagina, which creates a compression forcethat pulls the device and the distal balloon proximally to engageagainst the interior portion of the internal os (also known as thecervical ostium or cervical os).

FIG. 2 illustrates ablation device 100 inserted into the uterus of apatient with balloons 108, 110, and 112 inflated as described above.Once the distal and proximal balloons are inflated, the central ballooncan be inflated to provide additional sealing along the length of thecervical canal. The middle balloon can also be the location of athermocouple or temperature sensor configured to sense temperaturereadings in the cervix. If these temperature readings reach a thresholdvalue, such as greater than 44 degrees C., the controller canautomatically pause vapor delivery to avoid patient injury. Thisthermocouple can be tested or verified at the start of the procedure bythe controller which queries the thermocouple following placement in thepatient to ensure the thermocouple is connected and reading atemperature.

After positioning the ablation device but prior to delivery of vapor, itcan be advantageous to assess the integrity of the uterus to test thatthe vapor delivery tip of the device is positioned within a sealeduterus and to test that there is flow between the inflow and outflowlumens, by performing an integrity test and a patency test. The amountof fluid and rate in which it flows into the uterine cavity can providethe physician an indication of the size of the uterine cavity andwhether the device is in a false passage. An integrity test can assessthat the uterus is sealed, and determine leaks originating from 1)perforations to the uterine wall, or 2) leaks from inadequate sealing atthe cervix or 3) leaks from the fallopian tubes.

A second test that made an assessment for patency, referred to as thedevice lumens patency test or patency test, could provide an indicationto the physician whether the device was clogged with debris or placedwithin a false passage. This additional information to the physician, inconjunction with the integrity test, can provide greater assurance tothe physician of device location during “blind” endometrial ablationprocedures.

In clinical use, a uterine integrity and patency test could be usefulfor additional uterine procedures besides uterine ablation proceduressuch as the implantation of a device, implant, or a diagnostic ortherapeutic agent. In these cases, a separate unit or module that canconduct a uterine integrity and patency test, sequentially, separately,or individually, with a separate uterine cavity introducer can beemployed without a uterine ablation device or system.

In one embodiment, a uterine integrity test can contain the followingelements and steps. Referring to FIGS. 1A-1B and FIG. 2, gas/fluidsource 122 can be connected to pressure regulator 124 comprising eitherone regulator or an additional back pressure regulator. The gas/fluidsource can contain a gas, such as CO₂, or inert gases, or a fluid, suchas saline, Ringer's Lactate, non-isotonic solutions, glycerine, andmineral oil for example. The regulator 124 can be configured to keep thepressure of the external gas source below a safety threshold value. Inone embodiment, the safety threshold value can be approximately 70 mmHg. The actual pressure amount or graduation may not be monitored andmay not need to be. The fluid or gas from gas/fluid source 122 can bedriven at a constant pressure bounded by the safety threshold value(e.g., can be bounded by the maximum pressure the uterus will see duringtreatment, such as 70 mm Hg). In addition, it can be useful to operate auterine integrity test at a pressure equal to higher than the pressurerequired for conducting the endometrial ablation or other uterineprocedure.

In one embodiment, gas/fluid pressure can be achieved by elevating thegas/fluid source 122 a height distance above the uterine cavity tocreate pressure. This height elevation can be verified by a measuringstick, tape or laser. An example of a clinically used height for asaline bag would be at least 30 inches above the patient's uterus. Atthis height, the pressure would be between 50 and 70 mmHg. This pressureis low enough to be below the reported opening pressure of the fallopiantubes. In addition, a pressure sensor within the uterine cavity canverify that the appropriate amount of pressure is being applied for theintegrity test and patency tests. A self-adjusting feedback mechanismcan be employed to raise or lower the pressure of the saline source inresponse to pressure measurements taken from within the uterine cavity.As an example, this feedback mechanism can raise or lower the height ofthe saline source in response to the pressure measurements taken fromwithin the uterine cavity.

In some embodiments, the system can measure a flow rate of gas/fluidexiting the distal lumen of the uterine device or uterine ablationdevice during the uterine integrity test. This flow rate can also beused to determine the proper pressure or height of the gas/fluid source.For instance, flow rate readings can be taken while the gas/fluid sourceis at a certain height and the uterine device maintained within a knowncondition or in free space. As the height of the gas/fluid source israised or lowered, the flow rate of the gas/fluid will respondaccordingly until the gas/fluid source is placed at a height at thedesired flow rate, or is pressurized to the desired amount. Likewise,the gas/fluid source can be raised or lowered by a self-adjustingfeedback mechanism in response to the measured flow rate.

In some embodiments, the uterine ablation device can further include aflow meter 126 having a read out mechanism (not shown) to the end user.In one embodiment, the flow meter can comprise an ultrasound sensor, oran optical sensor configured to sense the drip rate of the gas/fluid. Insome embodiments, the flow meter can be disposed near distal tip 106 ofthe device. In other embodiments, the flow meter can be disposed withinan outflow lumen of the device. In yet another embodiment, the flowmeter can be disposed external to the device but along the flow pathbetween gas/fluid source 122 and the ablation device. The flow meter canbe configured to measure and report a flow rate of fluid/gas or vapor asit moves through or exits the uterine ablation device. The read outmechanism can be numerical, graphical, or icon based. Other variationsinclude various audio and visual signals, indicia, qualitative indicia,alarms, and color identifiers. A filter may or may not be attached tothe flow meter.

Referring to FIGS. 2 and 3, to perform a uterine integrity test, gas,such as CO₂, or a fluid, such as saline, can be delivered from thegas/fluid source 122, through a pressure regulator, and through a flowmeter 126 into the uterine ablation device 100. As shown in FIG. 3, thegas/fluid can be delivered into the uterus via both inflow lumen 129 andoutflow lumen 131. In one specific embodiment, a saline such as 0.9%NaCl can be delivered into the uterus during a uterine integrity test,to determine whether there are leaks in the uterus or cervical canalthrough which vapor could escape during an ablation procedure. Theuterine ablation device 100 can be coupled to an energy generator 124and controller 123 for uterine ablation therapy. The vapor generator canbe, for example, a vapor generator (as shown), but can also be any othertype of energy generator, such as an RF energy generator, a cryotherapygenerator, etc. Any type of energy modality can be used to ablate ortreat the uterus after performing the integrity and patency testsdescribed herein. The energy generator 124 can also include an air pumpconfigured to supply air to the various balloons in the system, such asthe distal, central, and proximal balloons or the balloon valves.

In one embodiment, a one way valve 127 as seen in FIG. 3 can be locatedbetween the flow meter 126 and the uterine ablation device 100. In othervariations the one way valve 127 can be located in the handle of theuterine ablation device 100 as well as other components such as the flowmeter 126 and valves 128 a, 128 b, and 128 c. The one way valve canreduce or eliminate retrograde flow of saline during uterinecontractions. The one way valve is characterized as providing lowresistance to flow in one direction (towards the uterine cavity) andhigh resistance to flow in the retrograde direction (towards thegas/fluid source). Advantageously the one way valve can stabilize flowvalues because retrograde flow values are eliminated. By reducing thesinusoidal wave patterns that can be caused by uterine contractions orrelaxations, movements by the patient, or inadvertent manipulations ofthe inflow line or the patient herself by the physician or medicalstaff, the procedure time is reduced. This filtering out of negativeflow values isolates positive components of flow, reduces noise in flowrate values, thereby accelerating the interpretation of flow rate dataand reducing procedural time. A fiso airline can connect a referencepressure transducer 125 to the outflow line of the integrity test salineflow pathway.

A controller of the uterine ablation device, either integrated into thedevice or into the vapor generator coupled to the device, can beconfigured to open and close valves 128 a, 128 b, and 128 c to allow gasor fluid to flow from source 122 into the inflow and outflow lumens 129and 131 of the ablation device 100. Valves 128 a, 128 b, and 128 c canbe any type of valve known in the art, such as solenoid valves,inflatable balloons, air cylinders, or electric/hydraulic actuators orcams and gears. During a uterine integrity test, the controller can beconfigured to open valves 128 a and 128 b and close valve 128 c, toprevent passage of gas/fluid into the waste container 133. This allowsgas or fluid to flow from source 122, through flow meter 126, throughone way valve 127 and valves 127 a and 128 b, and into inflow lumen 129and outflow lumen 131. As the gas or fluid enters the uterus, the flowmeter can measure an integrity flow rate of the gas or fluid.

In one embodiment, the controller of the uterine ablation device or thevapor generator can run an integrity test algorithm to determine if theuterus is sealed. The algorithm can analyze data from the flow meterduring the integrity test as gas/fluid is delivered into the uterus.Specifically, the algorithm can analyze a maximum flow rate and aminimum flow rate during an integrity test time window. The integritytest time window can be, for example, a rolling time window of apre-selected duration. In one specific embodiment, the algorithmanalyzes a maximum flow rate and a minimum flow rate continuously duringa rolling 15-second integrity test time window. For each rollingintegrity test time window, the minimum and maximum flow rates can becalculated. The difference between the minimum and maximum flow rates ineach integrity test time window can be calculated to yield a delta flowvalue (maximum flow rate minus minimum flow rate), which can be used asan indicator of the stability of flow. For example, the larger the deltaflow value, the less stable the flow of gas/fluid, and the smaller thedelta flow value, the more stable the flow of gas/fluid. If the maximumflow rate and the delta flow value of gas or fluid stabilizes below anintegrity threshold value, the controller can determine that the uterusis sealed. Importantly, the test is comprised of two algorithms thatcompare flow to an integrity threshold value concurrently with a secondalgorithm that compares the delta flow value to the integrity thresholdvalue, and uses both of these comparisons to determine the ultimateoutcome of the integrity test. The application of both of thesecomparisons provides greater sensitivity in the test results.

In some embodiments, this integrity flow rate delta threshold value canbe approximately 5 ml/min. Therefore, in some embodiments, a uterus isconsidered to “pass” the uterine integrity test if both the maximum flowrate and the integrity flow rate delta threshold value are below 5ml/min over a rolling integrity test time window. Alternatively, thetest can include different thresholds for maximum flow rate and thedelta flow value.

In some embodiments, the uterine integrity test can run for a pre-settime period. For example, the test can run for 60 seconds, andsubsequent rolling 15-second windows can be analyzed to determine if theuterus is sealed during the 60 second time period. In anotherembodiment, the delta flow value can be defined as a standard deviationof the average flow that is compared to a threshold value. This deltaflow value can then be compared to the threshold value to determine ifthe uterus is sealed.

In some embodiments, the return channel comprises a valve 128 c, such asa solenoid valve, air cylinder, electric/hydraulic actuators, cams andgears or pump/inflatable balloon, which can be activated upon the startof the integrity test to close off the egress of the gas/fluid throughthe return channel of the uterine ablation device. When the return flowof gas/fluid through the return channel is stopped with the valve, achange of flow can be detected by the flow meter 126 on the input line.In addition to determining if there is a leak or if the device ispositioned properly, the specifics of the changes in flow (e.g., how theflow reacts to closing of the return line with the valve) can providethe following the indications in some cases: a) the size of the uterinecavity; and b) the presence of a leak or lack of integrity in thesystem. For instance in clinical use with uteri of varying sizes, anintegration under the graphical curve of flow rate versus time providesa volume assessment of the size of uterine cavity. The amount of volumecan provide the physician information not only on the size of theuterus, but whether the device is improperly embedded in a false passage(smaller volume amount) or in the peritoneal cavity (larger volumeamount).

Immediately after performing the integrity test above, the amount offlow in the inflow and outflow channels can be measured in a patencytest and used to determine the presence of an obstruction that mayaffect the flow of vapor during the ablation procedure. Based on thisdetermination or patency test, the device may be repositioned orreplaced prior to delivery of vapor. For example, in one embodiment,referring to FIG. 4, a method of performing a patency test can comprisedelivering gas or fluid from inflow lumen 129 of the uterine device intothe uterus, also referred to as the fluid infusion tip, removing gas orfluid from the uterus with outflow lumen 131 of the uterine device, alsoreferred to as the fluid outflow tip, and determining that the uterinedevice is not clogged or embedded in tissue if a flow rate of gas orfluid is observed in the flow meter of the inflow lumen of the uterinedevice. In FIGS. 3-4, valves 128 a and 128 b control the flow ofgas/fluid to the uterine ablation device 100 and valve 128 c control theflow of gas/fluid from the outflow lumen 131 into the outflow canisteror waste container 133. Control of the valves 128 a and 128 b and 128 ccan be performed by a separate controller and software unit shown as123.

If it has been determined that the uterus is sealed based on theintegrity test performed and described in FIG. 3, the controller canalso be configured to perform a patency test. In one embodiment,referring to FIG. 4, the controller can be configured to open valves 128b and 128 c, but close valve 128 a. This allows gas or fluid to flowfrom source 122, through flow meter 126, through one way valve 127 andvalve 128 b, and into inflow lumen 129. Gas or fluid can be removedthrough outflow lumen 131, through valve 128 c, and into a wastecontainer 133. As the gas or fluid enters and is removed from theuterus, the flow meter can measure a patency flow rate of the gas orfluid. If the patency flow rate is maintained above a patency flow ratethreshold value, the controller can determine that the device is notclogged or embedded into tissue. In some embodiments, observing ormeasuring a flow of fluid or gas in outflow lumen 131 can be used todetermine that the device is not clogged or embedded in tissue. A flowrate above a patency test threshold during a rolling patency test timewindow can indicate that the lumens are not clogged or that the distalend of the uterine ablation device is not embedded into tissue.

In one specific embodiment, the patency test threshold can be greaterthan 5 ml/min, and the rolling patency test time window can be a 5second time period. Thus, the flow meter can measure the patency flowrate in rolling patency time windows (e.g., rolling 5 second periods)and the controller can analyze the measured rate. If the patency flowrate is maintained above the patency test threshold (e.g., 5 ml/min)during a rolling patency time window, then the patency test isconsidered passed and the test can be stopped. Passing the patency testindicates that the uterine ablation device is not obstructed or placedin false passage. If the patency test threshold is not satisfied, thephysician should repeat the insertion steps and/or repeat the integritytest and patency test prior to initiating uterine ablation. When thepatency flow rate is below the threshold of 5 ml/min during the rollingpatency test time window, the uterine ablation device may need to berepositioned.

During the transition from the end of integrity test to the start of thepatency test, the uterine cavity can be substantially filled with thegas/fluid provided during the integrity test. As described above, theclosed outflow valve during the integrity test prevents gas or fluidfrom exiting the uterine cavity into the waste container 133. In oneembodiment, it is desirable for valve 128 c to be opened only partiallyin the range of 20-50% open for a flow rate greater than 5 ml/min andless than 40 ml/min so the uterine cavity distension achieved during theintegrity test is temporarily maintained when the patency test checksfor open flow through the uterine ablation device. Certain types ofvalves are better suited for partial opening. For example, balloonvalves can be pulsed at various duty cycles to partially open the valve.The higher the duty cycle, the more quickly the valve can be opened.Partial opening of the valve prevents the uterine cavity from collapsingtoo quickly around the tip of the uterine ablation device which, in someinstances, may cause a false positive failure of the patency test. Inone embodiment, partial opening of the valve can be achieved by pulsingthe opening of the valve at a specified duty cycle until flow throughthe vapor probe begins, or alternatively until the uterine pressurebegins to drop. In another embodiment, the valve 128 c can be openedrapidly just until flow through the valve begins. This rapid dropopening of the valve can be achieved by pulsing the valve initially witha high duty cycle, then shortening the pulsing (or lowering the dutycycle) as the valve approaches the range where flow through the valvebegins. Once the patency flow rate increases above a threshold (or by aspecific rate of increase), the valve can be maintained.

In one specific embodiment, the valve 128 c can be a balloon filled toas much as 20 psig to occlude the tubing leading to waste container 133.The balloon valve can be pulsed open for up to 40 msec every 200 msecuntil the balloon pressure falls to as low as 5 psig. The valve openingtime can then be reduced even further until the balloon pressure fallsto between 3-4 psig. The valve can continue to be pulsed until flowincreases to a level of 0.20 ml/min or until flow rises above thethreshold value (e.g., above 5 ml/min).

FIG. 5 shows one specific embodiment where the outflow valve (e.g.,valve 128 c from FIG. 3) comprises an inflatable balloon. Inflating theballoon causes obstruction of the outflow lumen of the uterine ablationdevice, and deflating the balloon allows flow out of the device and intothe waste container. FIG. 5 shows the outflow valve pressure 136 (mmHg),the flow 138 (ml/min) through the uterine ablation device, and theuterine cavity pressure 140 (mmHg) during a typical patency test. At thecompletion of a typical integrity test, the cavity pressure should beabove 52 mmHg, the outflow valve pressure about 20 psi, and the flowthrough the uterine ablation device close to zero. In the first fewseconds of the patency test, the outflow valve pressure decreasesrapidly, then the rate of deflation decreases to zero as flow throughthe device begins, shown by arrow 142. The cavity pressure dropsgradually as flow increases. The patency algorithm can run concurrentlywith deflation of the outflow valve. In some embodiments, the deflationperiod of the outflow valve is typically from 3 to 40 msec.

Upon successful completion of the integrity and patency test, thecontroller of the uterine ablation device can automatically begin thetreatment process. The treatment process can comprise delivering vaporthrough the outflow lumen and vapor ports of the uterine ablationdevice. To collect condensate, debris, and byproducts of the ablationprocess, and free flowing vapor, the return lumen can include amicro-porous filter at its distal end. A fiber optic pressure sensor canbe located within the filter to ensure that the treatment pressure stayswithin a prescribed range. Pressure control can be achieved through aseries of valves that automatically engage and disengage to maintain thetreatment pressure within the prescribed range. If the pressure sensorrecords values too low or too high, the device can automatically pausevapor delivery and alert the physician of the condition that causeddiscontinuation of vapor delivery.

The uterine ablation device can further include an interrupt button andon-screen button to pause the procedure, if necessary, at any timeduring the procedure. As described above, a thermocouple can be locatedin the lumen that exhausts vapor from the uterine cavity. Thisthermocouple can provide post-procedural feedback on the temperature ofthe byproducts flowing through the outflow line and into the wastecontainer. This temperature provides an indication of the amount ofvapor that has circulated through the cavity and exited through thereturn lumen and outflow tubing.

Ablation is achieved by imposing elevated temperatures on theendometrial tissue for long enough duration to bring about cellnecrosis. Water vapor's unique feature is the high concentration ofthermal energy that is characteristic of the vapor phase. The easyextraction of the concentrated thermal energy by means of condensationenables high rates of heat transfer to be applied to the walls of theuterine cavity. The vapor is delivered in the uterine cavity at aprescribed pressure range and at a saturation temperature that isapproximately one degree above the normal boiling temperature of water.The uterine surface temperature is below that of the vapor, giving riseto sustained condensation.

The rate of utilized vapor flow can be auto-regulated by the rate ofcondensation and the rate at which heat penetrates the uterine tissue.If the rate of delivered vapor flow exceeds the auto-regulated value, itwill leave the uterine cavity through the return lumen and outflowtubing of the device. The thermal energy deposited on the uterine wallby condensation penetrates the uterine tissue by two transportmechanisms. One of these is heat conduction, which is a molecular-levelprocess that is indigenous to all media. A second transport mechanism isdue to blood perfusion, which is a seepage-like process. Heat is carriedby the perfusing blood, also called the “heat sink” effect. Therapeuticcell necrosis is achieved both maintaining elevated temperatures at theinner surface of the uterus and a long enough period to achieve thedesired depth of ablation. Since an excess of vapor at a prescribedpressure and period of time is supplied during the procedure to achieveablation, a large range of cavity sizes can be treated uniformly to thedesired depth without the need to adjust the treatment parameters.Uniformity of coverage within the cavity is achieved by the continuoussupply of steam that circulates within the cavity prior to exitingthrough the return lumen and outflow tubing.

At the completion of treatment at a predetermined time, which can beless than 140 seconds in one embodiment, the delivery of vapor isstopped by the controller and generator unit. After the cessation ofvapor delivery, the generator can query the intrauterine pressure sensorto ensure that internal pressure values have now dropped. Upon reachinga satisfactory level, the system automatically deflates the balloonsholding the device in the cervix and the physician can be notified thatthe delivery device is now ready for removal from the patient. Followingthis step, the system can unlock the uterine ablation device from thegenerator and the delivery device can be discarded.

Once treatment is completed, the system also prompts the end user ifanother patient is about to be treated. If so, the system repeats thesteps described above. If there is not another patient to be treated,the excess fluid can be drained from the generator.

As for additional details pertinent to the present invention, materialsand manufacturing techniques may be employed as within the level ofthose with skill in the relevant art. The same may hold true withrespect to method-based aspects of the invention in terms of additionalacts commonly or logically employed. Also, it is contemplated that anyoptional feature of the inventive variations described may be set forthand claimed independently, or in combination with any one or more of thefeatures described herein. Likewise, reference to a singular itemincludes the possibility that there are plural of the same itemspresent. More specifically, as used herein and in the appended claims,the singular forms “a,” “and,” “said,” and “the” include pluralreferents unless the context clearly dictates otherwise. It is furthernoted that the claims may be drafted to exclude any optional element. Assuch, this statement is intended to serve as antecedent basis for use ofsuch exclusive terminology as “solely,” “only” and the like inconnection with the recitation of claim elements, or use of a “negative”limitation. Unless defined otherwise herein, all technical andscientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. The breadth of the present invention is not to be limited bythe subject specification, but rather only by the plain meaning of theclaim terms employed.

1. (canceled)
 2. A method of testing a uterine ablation device prior to a uterine procedure, comprising the steps of: inflating at least one sealing balloon disposed on an elongate shaft of the uterine ablation device; pressurizing a tip cover disposed over the at least one sealing balloon and a portion of the elongate shaft; sensing a first pressure within the tip cover; sensing a second pressure within a vapor generator of the uterine ablation device; and comparing, with an electronic controller of the uterine ablation device, the first pressure within the tip cover to the second pressure within the vapor generator to register the first pressure sensor.
 3. The method of claim 2, wherein the at least one sealing balloon comprises a distal sealing balloon, a central sealing balloon, and a proximal sealing balloon.
 4. The method of claim 2, further comprising preventing, with the electronic controller, delivery of condensable vapor from the vapor generator if the at least one sealing balloon is leaking.
 5. The method of claim 2, further comprising: removing the tip cover from the uterine ablation device; and delivering condensable vapor from the vapor generator through the uterine ablation device into a uterus of a patient.
 6. The method of claim 2, wherein the at least one sealing balloon is inflated up to approximately 30 psi.
 7. The method of claim 2, wherein the at least one sealing balloon is inflated with air.
 8. The method of claim 2, wherein the at least one sealing balloon is inflated with a fluid.
 9. The method of claim 2, where in the inflating at least one sealing balloon step comprises inflating the at least one sealing balloon with an inflation source of the uterine ablation device.
 10. An endometrial vapor ablation system, comprising: a vapor generator comprising a first pressure sensor; a uterine ablation device coupled to the vapor generator, the uterine ablation device comprising: a shaft configured to be inserted into a uterine cavity of a patient; one or more lumens disposed in the shaft and coupled to the vapor generator; a second pressure sensor positioned near a distal end of the shaft; and a tip cover disposed over the distal end of the shaft and the second pressure sensor; a control system coupled to the uterine ablation device and the vapor generator, the control system being configured to pressurize the tip cover and compare a sensed pressure of the first pressure sensor to a sensed pressure of the second pressure sensor to register the second pressure sensor. 